This invention relates to a safety lock apparatus for an electrical plug and more particularly to such an apparatus which in conjunction with a standard padlock can be utilized to prevent insertion of the prongs of an electrical plug into an electrical outlet.
It has long been desirable to provide a simple mechanism to prevent the unauthorized use of an electrical appliance. For example, a child could possibly be injured if allowed to insert the prongs of a plug of an electrical appliance, such as an electric drill or the like, into an electrical outlet. Further, for example, there may be occasions where such electrical equipment such as televisions, video cassette recorders, home movie projectors, home and office computers, and the like, are not to be utilized by those without authorization or at inappropriate times. Finally, for example, it may be desirable to render the prongs of an electrical plug inaccessible so as to safeguard the easily bent prongs from damage thereby rendering the electrical appliance to which the electrical plug is coupled difficult to use.
Most prior art devices which have attempted to provide mechanisms to meet the above have generally operated by gripping or securing directly to the prongs of the electrical plug. For example, the devices disclosed in U.S. Pat. Nos. 4,413,488; 4,407,554; 3,662,320; 3,539,968; 3,345,600; 2,654,073; 2,844,805; and 2,733,416 all operate in this manner. These devices have several drawbacks, however. In some instances, the device disclosed is somewhat complex and difficult to use and requires manipulation of several parts. In other instances, the device will not operate to protect and/or prevent access to the prongs of the plug and thus can result in damage to the prongs and/or may encourage attempts to defeat the apparatus. Thus, in some instances, use of the device disclosed is unsatisfactory for the prongs are still generally accessible inviting attempts to defeat the apparatus. Such attempts may lead to injury if extreme caution is not taken. For example, some individuals may attempt to attach wires to the prongs for coupling to an electrical outlet. These efforts may lead to dangerous short-circuits and/or electrocution.
Other devices such as those disclosed in U.S. Pat. No. 2,955,272 and FIG. 5 of U.S. Pat. No. 2,654,073 have generally overcome some of the foregoing disadvantages in that the prongs of the plug are rendered inaccessible because the entire plug (plug body and prongs) is removably situated within a housing structure. However, each of these devices suffers drawbacks as well. In addition to the locking mechanism, these devices are comprised of a number of separate components which must be fastened together, and which are movable relative each other. Also, each of these devices generally presents an edge of a wall to the conductors of an electrical plug which exit from the housing and thus may introduce an additional source of danger to those attempting to defeat the apparatus. Additionally, the locking mechanism of these devices must be fastened securely to the device and is typically, therefore, not replaceable by the owner of the device should keys be lost and/or others obtain duplicate keys thus necessitating a change in the locking mechanism.
Accordingly, it has been one objective of the present invention to provide a safety lock apparatus for an electrical plug which is simple to use and does not, other than the locking mechanism, comprise component parts which must be put together.
A further objective of the present invention has been to provide such an apparatus which does not, other than the locking mechanism, comprise moving parts.
A yet further objective of the present invention has been to provide such an apparatus in which the prongs of the plug are rendered generally inaccessible thereby to prevent unauthorized access thereto and to minimize accidental electrical injury from attempts aimed at defeating the apparatus.
An even further objective of the present invention has been to provide such an apparatus which is easy to use to render the prongs of the plug generally inaccessible without securing the apparatus directly to the prongs.
A still further objective of the present invention has been to provide such an apparatus which is operable in conjunction with a standard easily replaceable padlock.